Termination for segmented steel tube bundle

ABSTRACT

A termination and anchorage for steel helical segmented steel tubing bundles includes a set of multiple separable anchor blocks to which the individual tubes in the bundle can be attached and a clamp assembly for securing and supporting the set of anchor blocks. Multiple comating annular arcuate outer anchor blocks for the outer tubes in the tubing bundle surround a central anchor block, for the center tube in the tubing bundle. The aggregation of anchor blocks is compactly assembled and held together by surrounding the assembled blocks with a separable clamp assembly.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application, pursuant to 35 U.S.C. 111(b), claims thebenefit of the filing date of provisional application Ser. No.60/616,802 filed Oct. 7, 2004, and entitled “Segmented Steel Tube BundleTermination.”

BACKGROUND OF THE INVENTION

1. Field Of The Invention

The present invention relates in general to a method and apparatus forconnectors for subsea operations. More particularly, the inventionrelates to the termination and axial anchorage of helical steel controltubing bundles used for control lines for subsea wellheads in petroleumproduction.

2. Description of the Related Art

Helical tubing bundles composed of a multiplicity of steel tubes areused routinely for hydraulic control functions and to convey otherfluids to subsea wellheads used in petroleum production. The individualtubes are maintained in constant relative angular positions and arearrayed in a bundle in a helical pattern about a central core tubewithout torsion in the manner used to lay a torsionally balanced wirecable or fiber rope. These relatively flexible tube bundles in somecases can be subjected to high tensions, particularly during theirsubsea installation.

Current means for terminating the ends of the tube bundles are bulky andheavy. Typically, the individual tubes at the end of a bundle aredisplaced somewhat from the bundle longitudinal axis in order to permitconnections to anchorages and other fittings to be made. These currentlyused end terminations are difficult to assemble, particularly if thetubes are welded into an anchor fitting, since sufficient space betweentubes must be provided for the welder to operate. Potted anchorageslikewise tend to heavy and bulky.

There exists a need for an apparatus and method that permits an easilyassembled anchorage for subsea tube bundles having high tensilecapacity.

SUMMARY OF THE INVENTION

The present invention relates in general to a method and apparatus forconnectors for subsea operations. More particularly, the inventionrelates to the termination and axial anchorage of helical steel controltubing bundles used for control lines for subsea wellheads in petroleumproduction.

The present invention provides a novel type of termination and anchoragefor steel helical control tubing bundles. The present invention includesa set of multiple separable anchor blocks to which the individual tubesin the bundle can be attached and a clamp assembly for securing andsupporting the set of anchor blocks.

One aspect of the present invention has a central anchor block, for thecenter tube in the tubing bundle, surrounded by multiple comatingannular arcuate outer anchor blocks for the outer tubes in the tubingbundle. The aggregation of anchor blocks is compactly assembled and heldtogether by surrounding the assembled blocks with a separable clampassembly. The separability of the anchor blocks permits maximum accessto the attachment points of the tubing to the anchors, while at the sametime allowing the tubings to be supported on minimal center-to-centerspacings.

Another aspect of the present invention is

The foregoing has outlined rather broadly several aspects of the presentinvention in order that the detailed description of the invention thatfollows may be better understood. Additional features and advantages ofthe invention will be described hereinafter which form the subject ofthe claims of the invention. It should be appreciated by those skilledin the art that the conception and the specific embodiment disclosedmight be readily utilized as a basis for modifying or redesigning thestructures for carrying out the same purposes as the invention. Itshould be realized by those skilled in the art that such equivalentconstructions do not depart from the spirit and scope of the inventionas set forth in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, and theadvantages thereof, reference is now made to the following descriptionstaken in conjunction with the accompanying drawings, in which:

FIG. 1 is an oblique view of the inlet/outlet end of a first embodimentof a tubing termination providing an anchorage for ten steel tubes.

FIG. 2 shows the tubing termination of FIG. 1 from its second side wherethe tubing bundle is attached.

FIG. 3 is an oblique exploded view of the tubing termination of FIGS. 1and 2.

FIG. 4 is an axial plan view of the tubing termination of FIGS. 1, 2,and 3, taken from the first side.

FIG. 5 is a longitudinal sectional view of the tubing termination ofFIGS. 1 to 4, wherein the section is taken along line 5-5 in FIG. 4.

FIG. 6 shows an oblique view of the tubing termination of FIG. 1 mountedon a bend limiter device.

FIG. 7 is a longitudinal section through the axis of the tubingtermination and bend limiter of FIG. 6.

FIG. 8 is an axial view from the first side of a second embodiment ofthe tubing termination of the present invention.

FIG. 9 shows an oblique exploded view of the tubing termination of FIG.8.

FIG. 10 is a longitudinal sectional view of the tubing termination ofFIGS. 8 and 9, taken along the line 10-10 in FIG. 8.

FIG. 11 is a plan view of a third embodiment of the tubing bundletermination of the present invention.

FIG. 12 is a vertical sectional view taken along line 12-12 of thetubing bundle termination shown in FIG. 11.

FIG. 13 is an oblique view of the tubing bundle termination shown inFIGS. 11 and 12.

FIG. 14 is a longitudinal sectional view of a conical tubing anchor ofthe third embodiment of the tube bundle termination of the presentinvention.

FIG. 15 is an oblique view of a typical helical tubing bundle consistingof seven equisized tubes.

FIG. 16 is an oblique view of a fourth embodiment of the tubing bundletermination of the present invention.

FIG. 17 is an oblique exploded view of the tubing bundle termination ofFIG. 16.

FIG. 18 is a plan view taken from the inlet/outlet side of the tubingbundle termination of FIGS. 16 and 17.

FIG. 19 is a longitudinal sectional view taken along line 19-19 of FIG.18.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides an apparatus and method that permits aneasily assembled anchorage for subsea tube bundles having high tensilecapacity.

The tubing terminations are intended for use with tubing bundlescomposed of a multiplicity of steel tubes, wherein the individual tubesare maintained in constant relative angular positions and are arrayed ina bundle in a helical pattern without torsion. In such a tubing bundle,a center tube serves as a core and multiple other tubes are arrayedaround the central tube by bending. The tubes need not all be the samesize. Normally, the center tube is the largest of the tubes in thebundle. The tubes at an end of a section of a tubing bundle areterminated by means of the tubing terminations of the present invention.Connections are made by either mechanical means or by arc welding.However, in the drawings for the present invention, only weldedconnections between the bundle tubes and the terminations are shown.

The components of the main structural elements of the tubing terminationembodiments of the present invention are typically made of carbon steel,high-strength/low-alloy steel, or stainless steel. A first embodiment 10of the tubing termination is shown in FIGS. 1 to 5.

Referring to FIGS. 1 and 2, the upper and lower sides of the tubingtermination 10 are shown. As shown in the drawings, the upper side ofthe termination corresponds to the inlet or outlet side for the anchoredtube bundle, while the lower side is where the tubes of the bundle areattached by welding. Strictly for providing a representative example,the tubing bundle in this case consists of ten equisized tubes, with asingle center tube 91 and nine outer tubes 92. A greater or lessernumber of tubes could be utilized, and the sizes can differ for theindividual tubes in a particular bundle.

FIG. 15 shows a typical tubing bundle 90 with a straight core tube 91and six helically spiraled tubes 92 closely arrayed around the coretube. For this tubing bundle 90 shown in FIG. 15, all seven tubes are ofthe same size.

The tubing termination 10 consists of a set of comating anchor blocks 11and 20, as well as a split clamp assembly 30 which holds the anchorblocks together. The center anchor block 11 supports the center tube 91of the bundle is a right circular cylinder having a transverse upperflange 12 and a coaxial right circular through hole 13. The outercylindrical surface 14 of the center anchor block 11 is comateable withthe outer anchor blocks 20 that serve to support the outer tubes 92 inthe tube bundle 90.

The inlet/outlet end 15 of the center tube 91 of the bundle 90 has aright circular cylindrical external upset having at its lower end aconical transition to the normal outer diameter of the center tube. Theexternal upset diameter is a slip fit to the through hole of the centeranchor block. Here, the bore of the inlet/outlet end 15 matches the boreof the center tube 91. The inlet/outlet end 15 is welded to each of theupper and lower transverse ends of the anchor block 11 bycircumferential fillet welds 17. The inlet/outlet end 15 is attached tothe center tube 91 by a circumferential butt or groove weld (not shownfor clarity). Here, the other, upper side of the end 15 is identical tothe lower side end and attachment by a circumferential butt or grooveweld is made there to a tube of equal size to that of the center tube91. Alternatively, either or both of the connections could be made bycommercially available compressive tube fittings.

Each outer anchor block 20 is an arcuate segment of an annular rightcircular cylindrical having an outwardly extending upper transverseflange 21, a right circular partial cylindrical inner face, asymmetrically positioned right circular through hole 29 parallel to theaxis of anchor block 20, and a right circular partial cylindrical outerface 23. The radius of the inner face 22 has the same radius as and iscomateable with the outer cylindrical surface 14 of the center anchorblock 11. The upper transverse face of the outer anchor block 20 abutsthe lower side of the upper flange 12 of the center anchor block 11 whenthe tubing termination is assembled. In the example shown here, all ofthe outer anchor blocks 20 are the same since the outer tubes 92 of thebundle 90 all have the same size.

A symmetrically positioned right circular through bolt hole 24 with itsaxis parallel to the longitudinal axis of the outer anchor block 20 andextending through upper flange 21 mounts downwardly extending hex-headretainer screw 25. The planar lateral sides 28 of outer anchor block 20can be coplanar with the axis of rotation of the block. Alternatively,as shown herein, the individual outer anchor blocks 20 can be made bycutting a solid annular ring with radial saw cuts which have a finitekerf width. The number of outer anchor blocks 20 corresponds to thenumber of outer tubes 92 in the tubing bundle 90.

The inlet/outlet end 27 for the attached outer bundle tube 92 supportedby outer anchor block 20 is structurally identical to the inlet/outletend 15 for the center tube 91. Circumferential butt or groove weldsagain make the connections of the inlet/outlet end 27 to the tube 92 andthe tube on the opposed end. The inlet/outlet end 27 has a close slipfit to the through hole 29 and is attached to the upper and lowertransverse faces of the anchor block by circumferential fillet welds 26.Again, either or both of the connections alternatively could be made bycommercially available compressive tube fittings.

The split clamp assembly 30 consists of first clamp half 31, secondclamp half 40, and the clamp studs 50 with clamp nuts 51 required todraw the clamp halves together. Sufficient space is provided between theclamp halves 31 and 40 so that they do not abut prior to fully clampingtogether the assembled anchor blocks 11 and 20. The split clamp assembly30 surrounds and retains the center anchor block 11 and its surroundingset of outer anchor blocks 20.

The first clamp half 31 and the second clamp half 40 are identicalexcept for their respective patterns of drilled and tapped retainerscrew holes 34. The arrangements of retainer screw holes are unequal forthe clamp halves in this case because there are an odd number of outeranchor blocks 20. In cases where the number of outer anchor blocks iseven, then the hole patterns of both clamp halves and hence the clamphalves 31 and 40 themselves are identical.

Each clamp half 31 and 40 has a right circular nearly semicylindricalannular body with the diameters greater than the axial length, anexternally extending transverse upper reinforcing flange 33 and 43respectively, and an externally extending transverse lower reinforcingflange 35. Drilled and tapped with their hole axes parallel to the axisof the clamp and into the upper transverse faces of the clamp halves 31and 40 are multiple retainer screw holes 34. The number of retainerscrew holes 34 is equal to the number of outer anchor blocks 20. Theinner nearly semicylindrical faces 36 of the clamp halves 31 and 40 areclose fits to the outer partial cylindrical faces 23 of the outer clampblocks 20. The upper transverse faces of the clamp halves abut the lowertransverse faces of the upper flanges 21 of the outer anchor blocks 20,while the retainer screws 25 are threadedly engaged with the retainerscrew holes to mount the outer clamp blocks 20 to the clamp halves.

Extending outwardly parallel to and slightly offset from the diametricalplane perpendicular to the vertical plane of symmetry for each clamphalf 31 and 40 are thick rectangular clamping ears 37. On each clampingear, two through clamping bolt holes 38 are drilled horizontallyperpendicular to the inner face of the clamping ears 37 symmetricallyabout the horizontal midplane of the clamp halves. When the clamp halves31 and 40 are assembled around the anchor blocks 11 and 20, the clampstuds 50 are extended through the clamping bolt holes 38 and then clampnuts 51 are used to draw the clamp halves together so that the tubingtermination 10 is rigidized.

FIGS. 6 and 7 show how the tubing termination 10 can be attached to abend limiting assembly 60 so that the tube bundle 90 will not beoverstressed by minor rotations at its anchorage 10. The bend limiterassembly 60 is a simple ball and socket arrangement with an integralabuttable flange travel stop 84 that serves to limit the amount ofrotation of the assembly. The tubing termination 10 can be mounted onthe ball or swivel head 80 portion of the bend limiting assembly 60. Thebend limiter assembly 60 consists of a lower socket 61, two identicalretainer halves 70, and the swivel head 80.

The lower socket 61 is a thick right circular cylindrical annular diskwith an outwardly protruding transverse flange 63 and an interiorcavity, both on its upper side. Flange 63 has a regular bolt hole circlepattern of transverse through holes in its periphery. The interiorcavityon its lower side has a coaxial spherically shaped cup 62 bore, whereinthe center of the spherical cup is located at the transverse uppershoulder 65 of the lower socket 61. An annular open-sided groove detentrecess 64 having a vertical outer side and a transverse bottom shoulderis located at the interior edge of the upper shoulder 65.

Two identical retainer halves 70 are formed by separating a modifiedlower socket assembly 61 into two segments with a diametrical cut. Theseretainer halves are mounted in mirror image positions inverted relativeto the lower socket 61 and are retained by studs 87 and hex nuts 88through the bolt holes in the flange 76 and the comating bolt holes inthe flange 63 of the lower socket. However, instead of having a detentrecess 64 on its lower shoulder 77 that is equivalent to the uppershoulder 65 of the lower socket 61, the retainer halves have a male boss71 which is comateable with the detent recess 64. Thus, the retainerhalves 70 each have a spherical cup 72, a flange 76, and a lowershoulder 77. When mounted together, the retainer halves 70 and the lowersocket 61 form a partial spherical pocket that serves as a support forthe spherical ball joint mounted in their interior.

Swivel head 80 is of annular construction and consists of, from itsupper end, the following coaxial elements: a transverse right circularannular flange 81, a thin wall circular tubular neck 83, and a lowerspherical surface 82 with a transverse flange travel stop 84 through itsspherical center. The outer diameter of the flange travel stop 84 issufficiently less than the interior recess of the lower socket 61 andthe retainer halves 70 that the swivel head 80 can rotate withoutcontacting the cylindrical interior walls of those parts. The diameterof the spherical surface 82 is comateable with and pivotable within thespherical recess formed by the spherical cups 62 and 72 of the lowersocket 61 and the retainer halves 70, respectively. The upper end ofswivel head 80 has a circular through bore 85 extending downwardly fromthe flange 81 to the center of the spherical surface. Below the centerof the spherical surface 82, the through bore 85 is outwardly flared.The amount of rotation which the swivel head can make about anyhorizontal axis through the spherical center of the socket formed by thespherical cups 62 and 72 is limited by the engagement of the travel stop84 with the interior transverse faces of the lower socket 61 and theretainer halves.

On the upper transverse face of the flange 81 are mounted two mirrorimage upwardly projecting mounting projections 86. These mountingprojections have vertical coplanar mounting faces that are offset fromthe vertical axis of the swivel head 80. The amount of offset of thesemounting faces is equal to the amount of offset of the back side of theclamping ears 37 of the split clamp assembly 30. Drilled and tappedhorizontal axis holes are provided in the mounting projection coplanarfaces so that the clamp studs 50 of the split clamp assembly can beengaged therein and the tubing termination 10 thereby mounted to themounting projections.

FIGS. 8, 9, and 10 show a second embodiment 100 of the tube bundletermination of the present invention. This second embodiment uses aconical socket in its clamp ring 130 to engage frustroconical surfacesin its outer anchor blocks 120, while the center anchor block 111 isretained by the engagement of its exterior frustroconical surfaces withcomating surfaces on the interior side of the outer anchor blocks. Asseen best in FIGS. 9 and 10, the center anchor block 111 is a cylinderwith transverse end surfaces, an axial through bore 113, and an outerfrustroconical surface 114 having a low taper angle. The center bundletube 91 is welded with a butt or groove weld to the inlet/outlet end 15for the tube. The inlet/outlet end 15 has a slip fit within the throughbore 113 and is retained therein by means of upper and lowercircumferential fillet welds 17 at the penetration of the inlet/outletend through the transverse faces of the anchor block 111.

The outer anchor blocks 120 are angular segments cut from an annularring having transverse ends and coaxial inner and outer frustroconicalsurfaces which taper in the same direction. The inner frustroconicalsurface has the same taper angle as the outer frustroconical surface 114of the center anchor block 111, and these two surfaces are comateableover a substantial portion of their axial length. Thus, each outeranchor block 120 has an inner partial frustroconical surface 122, anouter partial frustroconical surface 123, and two planar lateral sides128 formed by diametrical cuts of the annular ring described above. Athrough bore 129 extends through the outer anchor block 120 parallel tothe frustroconical axis and on the vertical plane of symmetry of theanchor block. An outer bundle tube 92 is welded with a butt or grooveweld to the inlet/outlet end 27 for the tube. The inlet/outlet end 27has a slip fit within the through bore 129 and is retained therein bymeans of upper and lower circumferential fillet welds 26 at thepenetration of the inlet/outlet end through the transverse faces of theanchor block 111.

The clamp ring 130 for tubing termination 100 is an annular rightcircular cylindrical ring having a coaxial inner frustroconical bore 136which is comateable with the outer partial frustroconical surfaces 123of the outer anchor blocks 120. The assembly of the tubing termination100 thus has the interior bore 136 of the clamp ring 130 filled with oneouter anchor block 120 for each outer tube 92 in the tubing bundle 90 toform a complete assemblage of outer anchor blocks to fill the conicalcup of the clamp ring. A center anchor block 111 is then positioned inthe center frustroconical socket formed by the inner partialfrustroconical surfaces 122 of the outer anchor blocks 120. The taperangles of the frustroconical surfaces of the assemble can be selected tomake the tapers either self-releasing or alternatively to have the angleof the comating frustroconical surfaces sufficiently small that theassembled anchor blocks are retained by friction against unintentionalrelease.

A third embodiment 200 of the tubing termination is similar to the firstembodiment 10, but the inlet/outlet ends 215 and 227 provided for thetubes 91 and 92 in the tube bundle 90 have frustroconical exteriorsurfaces which are socketed in comating frustroconical bores in theanchor blocks 211 and 220. FIGS. 11 through 14 show the details of tubebundle termination 200.

As shown in the drawings, the upper side of the termination 200corresponds to the inlet or outlet side for the anchored tube bundle 90,while the lower side is where the tubes of the bundle are attached bywelding. Strictly for providing a representative example, the tubingbundle in this case consists of seven equisized tubes, with a singlecenter tube 91 and six outer tubes 92.

The third embodiment tubing termination 200 consists of a set ofcomating anchor blocks 211 and 220, as well as a split clamp assembly 30which holds the anchor blocks together. The center anchor block 211 thatsupports the center tube 91 of the bundle is a right circular cylinderhaving a transverse upper flange 212 and a coaxial frustroconicalthrough hole 213. The diameter of hole 213 is reduced from top to thebottom end. The outer cylindrical surface 214 of the center anchor block211 is comateable with the outer anchor blocks 220 that serve to supportthe outer tubes 92 in the tube bundle 90. The inlet/outlet end 215 ofthe center tube 91 of the bundle 90 has a frustroconical external upsetwith a low angle and a downwardly reducing diameter. The inlet/outletend 215 has at its lower end a conical transition to the normal outerdiameter of the center tube 91. The external upset frustroconicalsurface is comateable with the through hole 213 of the center anchorblock. Here, the bore of the inlet/outlet end 215 matches the bore ofthe center tube 91. The inlet/outlet end 215 is not welded to the anchorblock 211, but is instead retained by frictional engagement. Theinlet/outlet end 215 is attached to the center tube 91 by acircumferential butt or groove weld (not shown for clarity). Here, theother, upper side of the end 215 is identical to the lower side end andattachment by a circumferential butt or groove weld is made there to atube of equal size to that of the center tube 91. Alternatively, eitheror both of the connections could be made by commercially availablecompressive tube fittings.

Each outer anchor block 220 is an arcuate segment of an annular rightcircular cylindrical having an outwardly extending upper transverseflange 221, a right circular partial cylindrical inner face 222, asymmetrically positioned frustroconical through hole 229 parallel to theaxis of anchor block 220, and a right circular partial cylindrical outerface 223. The radius of the inner face 222 is comateable with the outercylindrical surface 214 of the center anchor block 211. The uppertransverse face of the outer anchor block 220 abuts the lower side ofthe upper flange 212 of the center anchor block 211 when the tubingtermination is assembled. As shown here, all of the outer anchor blocks220 are the same since the outer tubes 92 of the bundle 90 all have thesame size. A symmetrically positioned right circular through bolt hole224 with its axis parallel to the longitudinal axis of the outer anchorblock 220 and extending through upper flange 221 mounts downwardlyextending hex-head retainer screw 225. The planar lateral sides 228 ofouter anchor block 220 can be coplanar with the axis of rotation of theblock. Alternatively, as shown herein, the individual outer anchorblocks 220 can be made by cutting a solid annular ring with radial sawcuts which have a finite kerf width. The number of outer anchor blocks220 corresponds to the number of outer tubes 92 in the tubing bundle 90.

The inlet/outlet end 227 for the attached outer bundle tube 92 supportedby outer anchor block 220 is structurally identical to the inlet/outletend 215 for the center tube 91. The connections of the inlet/outlet end227 to the tube 92 and the tube on the opposed end are again made bycircumferential butt or groove welds. The inlet/outlet end 227 is firmlycomateable with the through hole 229. Again, either or both of theconnections alternatively could be made by commercially availablecompressive tube fittings.

A fourth embodiment tubing termination 300, shown in FIGS. 17-19, is inmost respects very similar to the first embodiment 10. The differenceresides in the approaches to retaining the tube bundle and its attachedinner and outer anchor blocks in the split clamp assembly whenever thereis an outward thrust on the bundle. In the case of tubing termination300, the anchor blocks 311 and 320 are both restrained in axial motionin either direction by flanges on both ends of the anchor blocks.

Tubing termination 300 consists of a set of comating anchor blocks 311and 320, as well as a split clamp assembly 30 that holds the anchorblocks together. The split clamp assembly is the same in all details asis used for the first embodiment 100. The center anchor block 311 thatsupports the center tube 91 of the bundle is a right circular cylinderhaving a transverse upper flange 312, a coaxial right circular throughhole 313, and a transverse lower flange 318 that is a mirror image ofthe upper flange 312.

The outer cylindrical surface 314 of the center anchor block 311 iscomateable with the outer anchor blocks 320 that serve to support theouter tubes 92 in the tube bundle 90. The inlet/outlet end 15 of thecenter tube 91 of the bundle 90 has a right circular cylindricalexternal upset having at its lower end a conical transition to thenormal outer diameter of the center tube. The external upset diameter isa slip fit to the through hole of the center anchor block. Here, thebore of the inlet/outlet end 15 matches the bore of the center tube 91.The inlet/outlet end 15 is welded to each of the upper and lowertransverse ends of the anchor block 311 by circumferential fillet welds17. The inlet/outlet end 15 is attached to the center tube 91 by acircumferential butt or groove weld (not shown for clarity). Here, theother, upper side of the end 15 is identical to the lower side end andattachment by a circumferential butt or groove weld is made there to atube of equal size to that of the center tube 91. Alternatively, eitheror both of the connections could be made by commercially availablecompressive tube fittings.

Each outer anchor block 320 is an arcuate segment of an annular rightcircular cylindrical having an outwardly extending upper transverseflange 321, a right circular partial cylindrical inner face 322, asymmetrically positioned right circular through hole 229 parallel to theaxis of anchor block 320, a right circular partial cylindrical outerface 323, and an outwardly extending transverse lower flange 330. Theradius of the inner face 322 has the same radius as and is comateablewith the outer cylindrical surface 314 of the center anchor block 311.The upper transverse face of the outer anchor block 320 abuts the lowerside of the upper flange 312 of the center anchor block 311 when thetubing termination is assembled. Likewise, the lower transverse face ofthe outer anchor block 320 abuts the upper side of the lower flange 318of the center anchor block 311 when the tubing termination 300 isassembled.

As shown here, all of the outer anchor blocks 320 are the same since theouter tubes 92 of the bundle 90 all have the same size. The planarlateral sides 328 of outer anchor block 320 can be coplanar with theaxis of rotation of the block. Alternatively, as shown herein, theindividual outer anchor blocks 320 can be made by cutting a solidannular ring with radial saw cuts which have a finite kerf width. Thenumber of outer anchor blocks 320 corresponds to the number of outertubes 92 in the tubing bundle 90.

The inlet/outlet end 27 for the attached outer bundle tube 92 supportedby outer anchor block 320 is structurally identical to the inlet/outletend 15 for the center tube 91. The connections of the inlet/outlet end27 to the tube 92 and the tube on the opposed end are again made bycircumferential butt or groove welds. The inlet/outlet end 27 has aclose slip fit to the through hole 329 and is attached to the upper andlower transverse faces of the anchor block by circumferential filletwelds 26. Again, either or both of the connections alternatively couldbe made by commercially available compressive tube fittings.

OPERATION OF THE INVENTION

The operation of the tube bundle terminations of the present inventionis concerned with the assembly of the structures, since the apparatus isstationary and passive following assembly. The characteristic of thetube bundle construction which facilitates the use of the type ofstructural arrangement used in the present invention is the lack oftorsion induced in the individual tubes when the bundle is fabricated.The outer tubes in the bundle are laid into their helical patternutilizing only bending, rather than torsion, while the center tube isneither bent nor twisted. This causes the maintenance of alignmentbetween the tube ends of the bundle and the elements of the tube bundletermination to be much easier when the anchor blocks of the terminationare separated to attach the tubes. Generally, following the attachmentof the tube bundle terminations to the tubes, only elastic bending ofthe separated outer tubes is required to reestablish the desired compactbundle geometry at the end of the bundle.

The assembly of the tube bundle termination 100 proceeds as follows. Theends of the outer tubes of the bundle at the end of the bundle areseparated sufficiently so that there is sufficient room for a welder tooperate around any one of the tubes in the bundle. At this point, acircumferential butt or groove weld is made to align and join each ofthe outer tubes 92 and the inner tube 91 to an outer tube inlet/outletend 27 or an inner tube inlet/outlet end 15, respectively. Followingthis, the inner tube inlet/outlet end 15 and each of the outer tubeinlet/outlet ends 27 is slipped into the through bore 13 of centeranchor block 1 or the through bore 29 of outer anchor block 20, asappropriate.

At this point, the anchor blocks 11 and 20 are reassembled byelastically bending the tubes 92 into their packed pattern as shown inFIGS. 1, 2, and 4. Following this, the split clamp assembly 30 isassembled around the assembled anchor block pattern by engaging theclamp halves 31 and 40 around the anchor blocks and then tightening thenuts 51 on the studs 50 after insertion of the studs through theclamping bolt holes 38. At this point, match marks between each tubeinlet/outlet end 15 or 27 and its corresponding anchor block can bemade. Alternatively, tack welds of the tube inlet/outlet ends 15 or 27with their respective anchor blocks 11 or 20 can be made to hold thedesired alignment therebetween. At this point, the clamp assembly 30 canbe removed, the anchor blocks reseparated, and the circumferentialfillet welds 17 made to rigidly affix the inlet/outlet ends 15 or 27 totheir respective blocks. If tack welds were not used to hold alignment,then following anchor block separation, the blocks are aligned withtheir respective tubes using the marks prior to the making of the finalwelds 17.

When the connecting welds 17 are completed, the anchor blocks 11 and 20can be reclustered and the assembly completed by clamping the assembly10 together using the split clamp assembly 30. At this time, the boltholes 24 of the outer anchor blocks 20 are aligned with their respectiveretainer screw holes 34 and 44 in the first clamp half 31 and secondclamp half 40, respectively. Engagement of the retainer screws 25through the bolt holes 24 and into the retainer screw holes 34 and 44completes the assembly of the clamp. After this assembly operation, thetube bundle termination 10 is fully rigidized and can resist axial loadsin the direction of the tube bundle 90 by abutment of the upper flange12 of the center anchor block 11 on the upper surface of the outeranchor blocks 20 and the abutment of the upper flange 21 of the outeranchor blocks 20 on the upper surface of the split clamp assembly 30.The retainer screws 25 and friction between the center anchor block 11and its surrounding outer anchor blocks 20 provide resistance to axialloads in the other direction.

If the tubing termination 10 is to be used with the bend limiterassembly 60 shown in FIGS. 6 and 7, the split clamp assembly 30 is firstremoved and the anchor blocks 11 and 20 and tubes 91 and 92 passedthrough the through bore 85 of the swivel head 80, assuming thatsufficient clearance is available. If the clearance is insufficient,then the bend limiter assembly 60 must be slid over the ends of thetubing bundle prior to welding the inlet/outlet tube ends 15 and 27 totheir respective anchor blocks 11 or 20. After the tubing termination100 is extended beyond the upper surface 81 of the swivel head 80 of thebend limiter assembly 60, the flange nuts 51 on one side of the splitclamp assembly 30 are removed so that the studs 50 can be engaged intothe drilled and tapped holes mounting projections 86 of the swivel head80 of the bend limiter assembly 60.

The assembly of the second embodiment 100 of the tube bundle terminationproceeds in a similar manner to that for the first embodiment 10. Forthe termination 100, the clamp ring 130 must be slipped over the end ofthe tube bundle 90 prior to the final assembly welds 17 being used tojoin the anchor blocks 111 and 120 to their respective inlet/outlet tubeends 15 and 27. The assembly of the clamp 130 onto the clustered anchorblocks 111 and 120 is performed by sliding the clamp 130 over theclustered anchor blocks until the inner frustroconical face 136 of theclamp is tightened onto the outer frustroconical surfaces 123 of theouter anchor blocks 120. At this point, abutment of the frustroconicalfaces of the anchor blocks 111 and 120 and clamp 130 resists axial loadsin the tube bundle direction. Loads in the opposite direction areresisted by friction between the frustroconical faces.

The assembly of the third embodiment 200 of the tube bundle terminationalso proceeds similarly to that of the first embodiment 10 with thefollowing exceptions. The third embodiment 200 utilizes frustroconicalsurfaces between the inlet/outlet tube ends 215 and 227 and theirrespective anchor blocks 211 and 220 to socket and thereby anchor theinlet/outlet end in the termination 200. Accordingly, the anchor blocks211 and 220 must be slipped over the ends of the tubes 91 and 92 of thetube bundle 90 prior to welding of the inlet/outlet tube ends 215 and227 to their respective tubes by butt or groove circumferential welds.Rotational alignment of the inlet/outlet tube ends is readily achievedwithout advance fitup or marking, since the inlet/outlet ends 215 and227 can freely rotate in their respective frustroconical through bores213 and 229 until pulling them firmly into abutment tightens them. Theassembly of the split clamp 30 and the retention in the clamp of theanchor blocks 211 and 220 is identical to that of termination 10.

The fourth embodiment of the tube bundle termination 300 is very similarto that of termination 10. The difference between the two embodiments isrelated to the means for resisting axial loads produced by thrust on theend of the tube bundle 90. The tube bundle termination 300 is assembledin a manner identical to that used for the termination 10. For thisembodiment 300 when axial tension is induced in the tube bundle 90, theupper flange 312 of the center anchor block 311 abuts the uppertransverse faces of the outer anchor blocks 320, while the upper flanges321 of the anchor blocks 320 abut the upper side of the split clampassembly 30. For thrust loads from the tube bundle 90, the lower flange318 of the center anchor block 311 abuts the lower transverse faces ofthe outer anchor blocks 320, while the lower flanges 330 of the anchorblocks 320 abut the lower side of the split clamp assembly 30. Note thatthe retainer screw holes 34 and 44 of the first and second clamp halves31 and 40, respectively, can be omitted for this embodiment.

ADVANTAGES OF THE INVENTION

The advantages of the present invention directly result from the abilityto physically separate the anchor blocks of the tube bundle terminationsby sufficient space that the necessary connecting welds between thetubes 91 and 92 of the tube bundle 90 and their respective inlet/outlettube ends can be readily made. This ability directly results from thesegmentation of the anchor assembly into a set of anchor blocks whereinone block is provided for each tube in the tube bundle. Likewise, if theinlet/outlet tube ends are directly welded to their respective inner andouter anchor blocks, as is the case for tube bundle terminations 10,100, and 300, the anchor blocks can be sufficiently separated to permiteasily making those welds.

Because of this ability to separate the anchor blocks, thecenter-to-center spacing of the tubes in the termination can bedecreased significantly, since welding does not have to be done in theinter-tube spaces of the assembled terminations of the presentinvention. Consequent to the compactness of the present invention, itsweight and cost for construction as well as the assembly cost aresignificantly reduced.

The present invention provided a more flexible means for terminatingtube bundles than conventional welding or potting the tubes into asocket with a plastic. Should there be a problem with one tube, thetermination assembly readily can be disassembled, repaired, andreassembled. This flexibility greatly improves the maintainability ofthe termination.

The termination 200 can be assembled with particular ease, so that itoffers the quickest assembly of the set of terminations of the presentinvention. For cases of very low thrust loads applied to the terminationby the tube bundle, the second embodiment 100 or the third embodiment200 are satisfactory. The first 10 and, particularly, the fourthembodiment 300 of the present invention offer very high resistance tothrust loads.

As readily may be understood by those skilled in the art, the presentinvention may be varied in its details without departing from the spiritof the invention. For example, the configuration of the inlet/outlettube ends may be varied. Likewise, compression tube fittings may beutilized as an alternative to welded connections between the tubes ofthe tube bundle and the terminations of the present invention.

1. A subsea termination device for a helical tubing bundle comprising:a) a center anchor block attached to a center tube of a tubing bundle;b) a plurality of outer anchor blocks, each outer anchor block attachedto an outer tube of the tubing bundle, wherein an interior surface ofeach outer anchor block is comateable with an outer surface of thecenter anchor block to form an anchor block assemblage; and c) a ringclamp engageable around the anchor block assemblage to thereby rigidizethe anchor block assemblage.
 2. The subsea termination device of claim1, wherein the center anchor block is attached to the center tube bywelding.
 3. The subsea termination device of claim 1, wherein the outeranchor blocks are attached to the outer tubes by welding.
 4. The subseatermination device of claim 1, wherein the ring clamp is a split clampassembly having a first clamp half and a second clamp half cojoined bythreaded fasteners.
 5. The subsea termination device of claim 4, whereina flange on each outer anchor block is mounted on the first or secondclamp half.
 6. The subsea termination device of claim 1, wherein eachouter anchor block comprises: a transverse flange, a right circularpartial cylindrical inner face, a symmetrically positioned rightcircular through hole, and a right circular partial cylindrical outerface.
 7. The subsea termination device of claim 1, wherein each outeranchor block is retained within two opposed transverse flanges of thecenter anchor block.
 8. The subsea termination device of claim 5,wherein the radius of the inner face of the outer anchor block has asubstantially similar radius as an outer cylindrical surface of thecenter anchor block.
 9. The subsea termination device of claim 1,wherein an upper transverse face of the outer anchor block abuts aflange of the center anchor block.
 10. The subsea termination device ofclaim 1, further comprising a bend limiting assembly.
 11. The subseatermination device of claim 10, wherein the bend limiting assemblyincludes a lower socket, two mirror-image retainer halves, and a swivelhead.
 12. The subsea termination device of claim 1, wherein the centeranchor block and the outer anchor blocks have comating frustoconicalsurfaces.
 13. The subsea termination device of claim 1, wherein theouter anchor blocks constitute a segmented ring.
 14. The subseatermination device of claim 1, wherein the center anchor block and theouter anchor blocks have a radially outwardly extending transverseflange, wherein the flange of the center anchor block abuts a side ofeach of the outer anchor blocks and the flange of the outer anchorblocks engages the ring clamp.
 15. A termination device comprising: a) acenter anchor block having an outer surface of rotation, wherein thecenter anchor block is attached to a center tube of a tubing bundle; b)a plurality of outer anchor blocks, each outer anchor block attached toan outer tube of the tubing bundle, wherein an interior surface of eachouter anchor block is comateable with an outer surface of the centeranchor block to form an anchor block assemblage; c) a ring clampengageable around the anchor block assemblage to thereby rigidize theanchor block assemblage; and d) a retaining means for restraining theaxial motion of the center and outer anchor blocks.
 16. The terminationdevice of claim 15, wherein the retaining means includes a pair ofopposed flanges on the inner and the outer anchor blocks.
 17. Thetermination device of claim 15, wherein the retaining means includes: a)a pair of opposed center anchor block flanges, one flange extendingradially outward from a first end of the center anchor block and asecond flange extending radially outward from a second end of the centeranchor block; b) a pair of opposed outer anchor block flanges, oneflange extending radially outward from a first end of each outer anchorblock and a second flange extending radially outward from a second endof each outer anchor block; c) the flange at the first end of the centeranchor block abuts the first end of each of the outer anchor blocks; d)the flanges at the first end of the outer anchor blocks abut a firstside of the ring clamp; e) the flange at the second end of the centeranchor block abuts the second end of each of the outer anchor blocks;and f) the flanges at the second end of the outer anchor blocks abut asecond side of the ring clamp; whereby the termination device permitsthe anchor block assemblage to resist axial motion in either direction.18. The termination device of claim 15, wherein the outer anchor blocksconstitute a segmented ring.
 19. The termination device of claim 15,wherein a) the outer surface of rotation of the center anchor block isfrustroconical with a taper in a first direction; b) the interiorsurface of each outer anchor block is frustroconical with a taper in thesame direction as the frustroconical outer surface of the center anchorblock and comateable with the outer surface of the center anchor block;c) an exterior surface of each outer anchor block is frustroconical witha taper in the same direction as the frustroconical outer surface of thecenter anchor block; and d) an inner face of the ring clamp isfrustroconical with a taper in the same direction as the frustroconicalouter surface of the center anchor block and comateable with theexterior surface of the outer anchor blocks, thereby permitting theanchor block assemblage to resist axial movement in the said taperdirection.
 20. The termination device of claim 15, further comprising abend limiting assembly.
 21. The termination device of claim 20, whereinthe bend limiting assembly consists of: a) a socket element having afrustrospherical internal cavity; b) a ball element having: i) acylindrical neck supporting a coaxial frustrospherical external upsetcomateable with the internal cavity of said socket element; ii) acoaxial through bore; and iii) a transverse mounting surface withanchorages for the attachment of the ring clamp, whereby the ballelement is rotatable in the socket element within limits imposed by theimpingement of the cylindrical neck against the socket element.